Mullite replaces platinum, a precious metal that is expensive to mine and limited in supply

University of Texas at Dallas scientists found that a material called mullite, which is from a family of oxides, could replace platinum on diesel exhaust from automotives.

Platinum has been the go-to material for diesel vehicles because diesel exhaust emits more nitric oxide and nitrogen dioxode than gasoline vehicles (however, diesel engines are generally more efficient). To reduce the amount of these pollutants from diesel exhaust, platinum is commonly used.

The problem is that platinum is a precious metal, mainly because it is limited and very expensive to mine. For 10 tons of platinum ore mined, only 1 ounce is usually usable.

Enter Dr. Kyeongjae Cho, study leader and professor of materials science and engineering and physics at UT Dallas. He and a team of researchers set out to find the alternative, and discovered that mullite was exactly what the doctor ordered.

After synthesizing mullite and using computer models to see how it consumes nitric oxide/nitrogen dioxode, it was discovered that an oxygen-based composition of mullite is not only cheaper to produce than platinum, but it also reduces diesel exhaust pollution 45 percent more than platinum.

"Our goal to move completely away from precious metals and replace them with oxides that can be seen commonly in the environment has been achieved," said Cho. "We've found new possibilities to create renewable, clean energy technology by designing new functional materials without being limited by the supply of precious metals."

This new mullite discovery is already being commercialized as Noxicat.